ICD-10-CM > K00-K95 > K55-K64 > K55 > K55.3 K55.3 Necrotizing enterocolitis Non-Billable/Non-Specific Type 1 Excludes necrotizing enterocolitis of newborn (P77.-) Type 2 Excludes necrotizing enterocolitis due to Clostridium difficile (A04.7-) Codes K55.30Necrotizing enterocolitis, unspecifiedK55.31Stage 1 necrotizing enterocolitisK55.32Stage 2 necrotizing enterocolitisK55.33Stage 3 necrotizing enterocolitis